The present invention relates to a display device, more particularly to a display device which is capable of easily performing synchronization of three-dimensional graphics with a high resolution.
Although a CRT display showed slow progress with regard to a resolution, the resolution is about to make rapid progress with introductions of new technologies represented by a liquid crystal display. Specifically, the resolution of the liquid crystal display can be increased relatively easily in comparison with the CRT display by performing a fine process on the liquid crystal display.
A personal computer (PC) comprises a device referred to as a graphics adapter, which performs a control to display an image on a display. The graphics adapter has a memory for writing the images displayed on the display. This memory is called a frame buffer.
If the resolution of the display is made to be, for example, four times as high as before, also a memory capacity of the frame buffer of the graphics adapter needs to be enlarged by four times. It should be noted that in order to display the image, a mere increase in the memory capacity does not suffice. A processing speed of peripheral circuits also requires to be made approximately four times as high. However, there are problems that this is not easy and that the cost of the display devices with features as described above becomes high.
A feature of the present invention is to solve the foregoing problems, and to realize a monitor system which incorporates a display device with high resolution at a low cost.
Another feature of the present invention is to provide a display device in such a monitor system, which makes it possible to perform a synchronization in switching a buffer, particularly a liquid crystal display device.
Another aspect of the present invention provides a liquid crystal display device as described below, which can be applied to the display device of the foregoing monitor system. The liquid crystal display device of the present invention comprises a liquid crystal panel composed of a plurality of sub-screens. The liquid crystal panel forms one screen by assembling images displayed on the sub-screens. First and second buffers are provided so as to correspond to each of the sub-screens. A writing selector is provided for selecting into which buffer of the first and second buffers image data supplied from the outside should be written. Finally, a display selector for selecting which image data written in the first and second buffers should be displayed on the sub-screens.
Still another feature according to the present invention is to provide a display device which comprises an image data storing section having a plurality of double buffers. A first selector is provided for each of the double buffers. The first selector selects which buffer of the double buffers image data transferred from the outside should be stored. A second selector is provided for each of the double buffers. The second selector selects from which buffer of the double buffers the image data should be read out. An image display panel displays an image based on the image data read out of the selected buffer by the second selector. Finally, a controller issues an instruction to the selector a buffer by using either the first or second selectors.
According to yet another feature of the present invention with regards to the display device, the second selector notifies the controller of completion of reading-out of the image data in all of the double buffers. The controller can issue an instruction to switch a selection to the first selector based on the notification from the second selector.
Yet another feature, according to the present invention is a method of displaying an image on a display device in which first and second frame buffers are provided so as to correspond to each of partial display areas obtained by dividing a display area. A first step reads out image data written in the second frame buffer, while image data is written into the first frame buffer. Another step is included for displaying image data read out from the second frame buffer on the partial display areas. Yet another step is disclosed for stopping an operation of the first frame buffer after completion of writing image data into the first frame buffer. Still another step is disclosed for reading out the image data written in the first frame buffer after stopping the operation of the first frame buffer, and displaying the image data read out from the first frame buffer on the partial display areas. A final step of writing image data into the second frame buffer is further disclosed.